Process for sterilizing and disinfecting



June 28, 1938. lw. KRUsE ET Al.

PROCESS vFOR STERILIZING ANP vDISINFECTING FiledvAug. 2z'. 1953 s sheets-sheet 1 lIIIIIII June 28, 1938. w KRUSE T AL 2,121,875

PROCESS FOR STERILIZING AND DISINFECTING Filed Aug. 2 3. 195s s sheets-snaai 2 i (Jr F1919 June 28', 12938. w. K'RUSE Er Al. I l ,2,121,875

PROCESS -FOR STERILIZING AND DISINFECTING Filqd Aug. 23. 1933 s sheets-sheets Rg/4 Fig. 19 ngz@ u) m' (l),

ik? 64 l1 l Im/enfers.' www Mmmm du Paten-ted June 1938 PATENT o1-fries PROCESS Fon s'rERILIzING AND DISINFECTING.

. Walter Kruseand Maximilian Johann Fischen. i Leipzig, Germany, assignors to Curt Angelini,

Leipzig, Germany Application August z3, 193s, serial No. 686,426y In Germany June 8, i1929 i v 5 claims'. (cl. 20d-24) We have filed applications in Germany on 8th Ju'ne, 1929; 29th December, 1930; 23rd March, 1932; '7th April, 1932; 7th April,- 1932 claiming the priority of 10th December, 1931; 15th May,

The present invention relates to processes and apparatuses for the production of oligodvnamically active substances for sterilizing and ldisinfecting. y 4

Itis known that silver and chlorine are substances whi'ch, even in the most highly diluted form (for example, in chloride-containing solutions containing lpart in 1 million parts or 1 part in several million parts), exert a sterilizing action on waterand also produce powerful disinfecting effects in the presence of other inorganic or organic solutions when brought into solution therein. Silver and. chlorine exhibiting the aforesaid properties are hereinafter termed oligodynamically active substances. 'The term oligodynamically active was originally employed by Ngeli only in connection with the'action ofv socalled pure metals in water to define the nature of the activity, and has since been employed by other writers in various slightly diierent meanings, but in this specification the term is'used in the above-defined sense. is based on the discovery that the so-called oligodynamic action of the metals, that is to lsay the Vgerm destroying action of the metals, particularly the precious metals, can be producedinthe highest degree by inserting the metals in `question as anodes in the circuit of an electric current. If, for example, two pieces of silver are suspended in any dilute electrolyte,.for example physiological common salt solution, and a weak current is passed through them, then only theanode silver plate becomes oligodynarnically active. If the said plate is placed on a cultivation surface which. has been sown with bacteria then it willbe 'o b-` served that after 24 hours the anode is surrounded by a space which is free from germs, whilst the space surrounding the cathode and the plate itself isv uniformly and thickly coated with bacte- ,45 ria colonies. The cathode. is meanwhile of pure discoveryis employed according to the invention in many novel technical applications. In the first place, silver or silvered chirurgical or hygienic instruments may, for example, be coatedl in dilute soda or common salt ,solution by means of The present invention the current passing through the anode with a 'layer of oligodynamically active substance,

which is then transmitted to the tissue in the living body and prevents infection. In particular,

such places as might be. damaged by pinching with forceps, tweezers, hooks, catheters and so forth in respect to their capacity as living organisms are protected against infection by the oligodynamically active substance.

It will, of course, be understood that the aforesaid action disappears gradually but itA can be renewed at any time by fresh anodization, activation, or' restoration of the oligodynamic action, and, in fact, the said operation may be effected whilst the apparatus is1 actually in the living body. The sterilization of the passagesof roots of teeth, which is known to be one of the most dimcult operations indentistry, can thus be effectedby inserting a silver wire which has been rendered active into the root passage and leaving it in this4 position, whilst from time to time by -means of adry battery, the cathode of which isv active 'substance adheres to the surfaces of the silver and physiological solution is thus gradually imparted by them to the living tissue, it is possible, in thecase of an electrolyte which is as weak as water and is only used in small quantitities, to effect sterilization very simply by either suspending in it a silver' plate which has previsilver electrodes of rod form and a dry battery-in a handleattached thereto, whereby within a few vseconds the necessary quantityof active material can. be introduced. yLarge quantities 4of water, particularly flowing water, can be sterilized if the coating of the silver by means4 of the current passing through the `anode is repeated from time to time or in a still simpler manner if an` intermittent or continuous current is passedthrough the silver anode, the cathode being composed of any desired suitable metal. The oligodynamic substance does not adhere in this case to the anode but is discharged from it in the form of clouds. For example, the water inya public bath (1000 cubic metres per day) was sterilized by employing an aggregate of plates which was not larger than the size of a hand arranged in front of the opening of the inlet pipe of the water container and provided with four silver anode plates measuring x 2 cm. which were fed with a continuous current of 1.25 amperes at 9 volts. Five copper plates arranged between the anodes externally thereof at a distance of 1 cm. were employed as cathodes. Provision was made by means of an automatic device to ensure that the passage of current was interrupted as soon as the ow of water ceased. Regular attention to the apparatus was hardly necessary but it was switched oi during the night, cleaned lby brushing from time to time and the silver electrodes which were connected together by means of a bow and weighed altogether 1 kilogramme wererenewed every three weeks because by that time they had dissolved except fora small residue. 'Ihe obvious idea of making the cathodes as well l y as the anodes of silver, and o f reversing the current from time to time was very soon given up, inasmuch as Vdisturbances arose which valmost defeated the objectin view. It is very important to construct the device in the proper form for the the differing constitution of the water which contained a much larger quantity of chlorides, constituents forming hardness and organic constituents, than the water employed in the rst mentioned bath installation. In order to avoid failmetres for water which is very impure.

ures itis thus necessary to determine in each lndividual case'the correct distance of the electrodes from one another.

The sterilization process for water is as sirnpleand inexpensive as is conceivably possi le, inasmuch as the cost of the current hardl comes into consideration and the amount, of silver-1 e'mployed islabout 15 to 20 grammes per thousand cubic metres for waters which are not very impure and about 50 grammes per thousand cubic Such quantities of silver are naturally entirely tasteless and harmless. l

It must be borne in4 mind that the oligodynamically active silver does not sterilize the water immediately but only in about 3 to 6 hours.

`When large water containers are at disposal the frame containing the aggregate of plates is mounted as above-described on the inlet pipe, i. e.

in front of the outlet opening thereof. If, however, the water before it is used has to pass over considerable distances aul intermediate arrangement may be employed in which the electrodes are preferably arranged concentrically and aremounted in ja T-piece inserted in the pipe in suchmanner that they are immersed fin' the Awater passing the pipe. In front of and'behind the T- piece shut-oir valves are l preferably arranged which are employed when itis necessary to renew or to clean the plate aggregate.

Inasmuch as experience has shown'that they 'oligodynamic effects are produced by pure substances and not, as has sometimes been maintained, by "contactf, itseemed to the applicants v that it must be possible to produce the said substances in a concentrated state. This has also been successfully effected in two ways. If the electrolytes are used in dilute solutions of N/500 a colloidal solution of active substance which can be stabilized by means of a protecting colloid, is obtained from the silver anode. If. now, the concentration of the'electrolytes is increased up to a figure of N/ 10 to N/20 a very nely divided powder is obtained which canbe easily removed from the anode and is very active. If still stronger solutions are useda slate-like material adhering to the silver is obtained which proves to be almost insoluble and inoperative.

It is, however, also possible to obtain oligodynamic effects if the current of low voltage passing through the anode is allowed to act on insolubleelectrodes, such as platinum, or Krupps metal, provided that a dilute electrolyte,.containing chlorides, is employed for\ carrying the, current.

Every natural water and also so-called dis.

tilled water contains, sumcient' quantities ci' chorides to develop under the inuence'of strong currents of-low voltage so much active chlorine,

on a non-corrodible anode that the Water is thereby sterilized, the oligodynamic eiect produced being precisely similar to that which is obtained in any natural water when silver anodes are used. In the latter case the chlorine passes on to the silver whilst in the former` case it is free. 'Ihis possibility has been hitherto overlooked although the production of chlorine from strong solutions of chloride has been known for a long time. I-Iitherto it was thought that ordinary water could only be sterilized by treating it with currents of high voltage which caused the development of active oxygen (03). According to the present invention the formation of ozone l' is intentionally prevented bythe use of currents oflow voltage for the reason that this gas smells badly and irritates the respiratory organs, whilst it does not operate so strongly bactericidally as the active chlorine. In order in spit/e oiqthis to' obtain sumciently strong currents which are necessary for the development of chlorine, the surfaces of the electrodes according to the invention are made as large as possible and their dise tance apart from one another is made as small as possible. Fory large quantities of water such as are employed for example for supplying vhath and similar installations, hotels and ships, a

tageously. mounted on the water pipe in question large plate device is used which may be advanin such manner thatthe gases (hydrogen and so forth) arising during the activation can escape. In this mannerone or more cubic metres of water per hour can be sterilized.

It is advantageous to add in the rst placeto the water which is to be sterilized some common salt, for example about 300 to 400 milligrammes per litre.- The taste is not altered therebybut the conductivity of the water andthe efficiency of the electric current is improved so that the ap? paratus maybe made smaller and the duration of the current treatment can be shortened. A further advantage of the addition of commonV salt resides in the fact that the natural waters which differ so considerably in ,their constitution are rendered similar to one another by the uniform addition of the comon salt. so that instructions for the use `of the apparatus can be given which hold good for each lindividual case. The addition of common salt according to the invention has l nothing to do with the proposal which has already been made to sterilize water by the electrolys'is of a strong .solution of conirnonv salt in a separate porous cell or acell bounded by a .diaphragm and allowing the chlorine which has developed to act upon the surrounding water by4 diffusion.

.As compared with the activation of the water of dental instruments for the purposei of internal l vquires to sterilize,'for `example when travelling,

or for household purposes, this fact is not of importance. The necessary supply of electricity is availableeverywhere nowadays. In a. ymotor car or motor-cycle accumulators `are available,

but in any case even the dry batters employed for pocket lamps suffice. The-Sina process which 'is suitable for small quantities of water thus forms a complement to the Cuma process, which latter serves for the sterilization of water on a large scale.

It is, however, also possible accordingto the same principle to sterilize very rapidly so-called physiological salt solutions as also hypoand hyper-tonic solutions serving for medical pur-` poses and thus to produce solutions having the highest degree of disinfecting power (similar to Dakins mouth wash employed in -the World War). 1 Inasmuch as the conductivity of solutions of this kind is much greater and theyield of active chlorine by'means of the current is very much more considerable, than with the ordinary water or waters to which only very little salt has been added, the apparatus can be made of still smaller size and it is sufficient to provide as electrodes two small platinum plates each having a-surface of 2 x 2 cm. and arranged parallel to one another at a distance of 1 to 2 millimetres apartin an insulating frame. If, now, the current from one or two accumulators is passed through the apparatus the sterilization of the salt solution takes place almost instantaneously. If the action of the current is prolonged to a period offfrom 10 to `20"minutes then the preparation of afdisinfecting .and therefore physiological solution is completed. Thel advantage offered by the ein ployment of this small apparatus fo'r the practical physician, for hospitals and for first-aid will be obvious. 1f. larger quantities of thesterilizing lor disinfecting solution are required the apparatus can naturally be constructed of greater size.

Some preferred constructional -forms of apparatuses for carrying out the process according to the invention in the various previously mentioned applications are illustrated by way of example in the accompanying drawings.

Referring to the drawings:

Figs. 1v and --2 each show an arrangement for the activation of chirurgical or Ihygienic silvered or silver instruments. l

The reference numeral I denotes a. base in which a dry battery 2 and a container 3 are arranged, which latter contains a dilute solution of Asoda or sodium chloride. In the solution a cathode 4 is immersed whichis arranged in` a linenbag and is conductlvely connected with the negative pole of the -dry battery. The positive pole of the battery is connected by means of a lead 5 and a clip terminal 6 with the instrument 1 which is to bey activated and which is immersed in the solution of sodium chloride.

The modified constructional form according to Fig. zdifers from that according to Fig. 1 only., in that the container 8 for the solution and thel disinfection. j .l l

An anode carrier I -and a cathode carrier II are provided which serve at one end for the. at-

tachmen't of projecting members I2 and I3 respectively forming the anode and cathode respectively and shown in Fig.' 3fas being removed from the carriers.- -The projecting members mounted in the carriers are connected by means of conducting members I4v and I5 respectively embedded in the supports and flexible leads I6 vand II respectively connected therewith, with the positive and negative poles respectively of a hand lamp battery I8. The current is measured by means of a milliamperemeter I9', 'and on the anode carrier I0 a switch 20 is provided.

Fig. 4 shows theapplica'tion of theinstrument in the tooth itself. The projecting member I2 lof the anode is located in the root passage whilst,

the projecting member I3 of the `cathode is sages reaches up to the surface of the tooth a reactivation may be effected in any desired time.

Figs. and 6 show inelevation and in section on line 6 6 of Fig. 5 to an enlarged scale respectively an instrument in which the electrodes, i. e. the anode and the cathode, which are in the form of wiresfare arranged in a common c'arrier 2I in such manner as to be insulated from one another. They arev both introduced together into vthe root passage .of the tooth,`

With this arrangement a stronger. activation is obtained.

Fig. '7 shows partly in elevation and partly in section ahand apparatus for the sterilization of small quantities of water. Two silver rods 22 and 23 are fixed in a housing 25 containing a pocket lamp battery 24 and serving as a handle, and

Fig. is an elevation of the interchangeable plate frame.

On an end flange 26 of the pipe 2'I/a plate 28 proyided in the middle with an lopening is screwed. 'I'he opening, which is rectangular, is .surrounded by `an insulatingframe 29 which is 'fixed to the plate and in which a frame 30 carrying the electrode plates is mounted. In the frame 30 four thick silver plate anodes 3| and five copper plate cathodes 32 are mounted. The

pressed up against the gum. Inasmuch as thv silver wire which is introduced into the root. pasanode plates are connected by means of a bridge 33 whilst the copper cathodes are connected on the two sides alternately by means of leads 34. The said arrangement is suitable for an upwardly directed water discharge. In the oase of a horizontal or downwardly directed discharge or a discharge inclined slightly to the horizontal, means are, of course, yprovided for attaching the plate frame and the plates.

Figs.l 11 and 12 show an arrangement for the sterilization of water flowing through apipe or being discharged from a pipe in a horizontal direction. In these figures: f

Fig. l1 is a longitudinal section taken on line II-I I .of Fig. 12,`- and Fig. 12 is a cross section taken on the line In the vertical branch arm 35 of a T-piece 36 the plate aggregate is suspended, this latter containing in concentric arrangement a thick tubular anode 31 of silver and an external and an internal thin copper tube cathode 38. The plate aggregate' is protected externally by means of an insulating shell 39. The latter is xedv to a. plate 42 by means of laterally arranged insulating carriers 140 in the interior of which the current leads 4I are arranged, the said plate 42 being fixed to the liange of the branch arm 35 by means of screws. On the outer side of the cover y 42 terminals 43 for the leads are arranged.

Fig. 13 shows an apparatus for the production of concentrated oligodynamically active substance in perspective.

The device consists of a tion of the dilute electrolytes, in which bath two thin silver plate anodes and three thirlcopper plate cathodes 46 are suspended. The anode and .cathode plates are connected by means of bridges 41 and 4B respectively. The said figure i3 also illustrates the current supply from a source of current together with a regulating resistance 4.9, an amperemeter 50 and a volt meter 5l. l

Figs. 14 and 15 show infront and in side elevation respectively an` apparatus constructed in the form of an immersion member provided with non-corrodible anodes for the .sterilization of small quantities of Water.

The part which is intended tov be immersed consists of nine plates 52 of Krupp steel Vza of about an area of 10 x 2 cm. which are fixed parallel to one another ata distance of 1 to 2 millimetres apart in a handle 53 and which serve alternately as an anode and cathode for current supplied by one or two accumulators. The plates are alternately connected as anodes and cathodes and are separated by means of insulating pins 54. The current is supplied to the plates through the handle.

Figs. 16 and 1'1 show an apparatus having noncorrodible anodes for the sterilization of larger quantities of water. y

Fig. 16 is a section taken on lineI l6-I6 of Fig. 1 7, and

Fig. 17 is a view from above. The.water to be sterilized passes from below through the pipe 55 into a funnel-shaped box 56 `mounted thereon. In the upper part 51 of the box, which part is of square cross section, an insulated plate frame 58 is mounted. The frame contains numerous plates 59 of Krupp steel Vza arranged parallel to one another and connected alternately as anodes and cathodes. To the box 56 which isopen at the top a box 6I likewise open at the top and provided with a lateral outlet 60 is connected by means of a flange. The Water flows in the sterilized condition downwards through the outlet 60 whilst the gases developed during the electrolysis can escape freely at the top.

bath 44 'for the recep- Figs. 18 to 20 show an immersion member having non-corrodible anodes for the sterilization of vphysiological solutions.

Fig. 18 is a side elevation,

Fig. 1,9 a longitudinal section, and

Fig. 20 a view of the under side.

The apparatus consists of two small platinum plates 62 each having a. surface of about 2 x 2 cm. and serving. as electrodes. xed at their outer part to insulating plates 63 and are arranged parallel to one another at a distance of 1 to`2 millimetres'apart upon a rod 64 serving as a handle. The current supply leads .for the small platinum plates are led through the interior of the rod or handle 64.

We claim:

1. A process for the production of oligodynamically active substances in water, on surgical instruments and in the form of concentrated solutions and powder, consisting in obtaining for these purposes oligodynamically active silver by passing an electric current throughV a dilute chloride-containing electrolyte ofv a strength of not more than N/20 between an insoluble cathode and a silver-containing anode; the voltage, the concentration of the electrolyte, the supercial area of the electrodes, and the distance `apart of the latter from one another being so chosen that currentdensitiesv of comparatively large magnitude are continuously maintained and lowr currentdensities are continuously avoided.

2. A process for the sterilization of water according to claim 1, in which anodes according to the composition of the water arel arranged at a distance of about 1 .to 2 centimeters away from the cathodes, the said distance varying with theV concentration of the electrolyte.

3. A process for the production of aligodynamically active substances in the form 0f col-l. loidal solutions which comprises passing a direct current from a silver anode to an insoluble cathode through a chloride solution containing a protective colloid and having a concentration ofapproximately N/500.

4. A process for the sterilization of water according to claim 1 in which the voltage is about 9 volts and the current density is approximately .8 ampere per sq. cm., and in which anodes according to the composition of the water Yare arranged at a distance of about 1 to 2 centimeters away from the cathodes, the said distance varying with the concentration of thel electrolyte.

5. The process according to claim 1 in which the oligodynamically active substances formed are obtained in the form of powder.

WALTER KRUSE. MAXIMILIAN JOHANN FISCHER.

The said plates are f' 

